Enhancement of Process Capabilities and Numerical Prediction of Geometric Profiles and Global Springback in Incrementally Formed AA 1050 Sheets

Abstract

In single point incremental forming (SPIF) process, parts suffer from dimensional inaccuracy and limited formability, mainly, due to occurrence of springback and abrupt fracture, respectively. Orientation imaging microscopy of the original AA1050 sheet revealed dislocated and distorted microstructure and texture in comparison to the same sheet preheated at different temperatures. The objective of this work is to investigate formability and geometrical accuracy due to variations in microstructure and texture of the sheet and to propose a methodology, which can predict the geometric profiles and springback effect at different preheating temperatures. The work reports enhanced formability and geometrical accuracy of parts formed by SPIF, owing to the reformation of grain structure due to preheating. However, preheating at higher temperatures, i.e., 330 and 500 °C deteriorated the surface quality, as homogenization of grain orientation led to orange peel effect. The proposed methodology, based on reverse engineering and numerical formulation, is capable of predicting two-dimensional cone and pyramid profiles as well as global spring back values associated with different preheating temperatures. The results predicted by proposed method were validated by experiments and could be implemented to enhance the accuracy of SPIF process.